Stacker crane construction

ABSTRACT

A stacker crane storage arrangement wherein a tray is supported for reversible extension transversely of a tower which is movable on a track, so as to deposit cargo laden pallets in cells or cubicles of open sides storage grids on both sides of the track. The tray of the tower is movable by a compact mechanism, utilizing telescopically and reversibly extending drive members carried by pairs of cantilever beams and driven by sprocket chains and hydraulic cylinders in a dual system which effects reversible motion of a tray to either side of the tower. The telescopic tray mechanism provides for moving a cargo laden tray to either a part distance or a full distance transversely of the tower, so that pallets can be stored in or retrieved from double depth storage grids. The specific racks or cells can hold two pallets in tandem, there being a first pallet position and a second pallet position in each cell. The arrangement and construction has features whereby very tall towers are usable.

Unite Wentz States tet [191 {451 Feb. 19, 1974 STACKER CRANE CONSTRUCTION [75] Inventor: Edward A. Wentz, Gaithersburg,

22 Filed: Nov. 15, 1971 21 Appl.No.: 198,917

Related US. Application Data [63] Continuation of Ser. No. 840,667, July 10, 1969,

Primary ExaminerRobert G. Sheridan Assistant Examiner-R. B. Johnson Attorney, Agent, or Firm-Zalkind, Horne & Shuster [57] ABSTRACT A stacker crane storage arrangement wherein a tray is supported for reversible extension transversely of a tower which is movable on a track, so as to deposit cargo laden pallets in cells or cubicles of open sides storage grids on both sides of the track. The tray of the tower is movable by a compact mechanism, utilizing telescopically and reversibly extending drive members carried by pairs of cantilever beams and driven by sprocket chains and hydraulic cylinders in a dual system which effects reversible motion of a tray to either side of the tower. The telescopic tray mechanism provides for moving a cargo laden tray to either a part distance or a full distance transversely of the tower, so that pallets can be stored in or retrieved from double depth storage grids. The specific racks or cells can hold two pallets in tandem, there being a first pallet position and a second pallet position in each cell. The arrangement and construction has features whereby very tall towers are usable.

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.R m 2% Q: N 8 9: E 0% ll 0% m m ww zoEmE mom w A D R 2; m 2 2% .w com 5 9% PATENTH] FEB] SL974 sum '15 or 1s .wv ZOE-50m mom PATENTED FEB] 9 I97 sum 15 or 16 STACKER CRANE CONSTRUCTION This is a continuation of application Ser. No. 840,667 filed July 10, 1969 now abandoned.

Briefly, the invention contemplates a roller mounted tower comprising a pair of spaced columns, intermediate spacing having an elevator in which a tray is disposed and supported for reciprocal vertical movement driven by a sprocket chain arrangement for raising or lowering cargo laden pallets. The tray is mounted on a telescopic transport mechanism for sliding movement to either side of the tower from a retracted or neutral position so as to insert or remove cargo laden pallets relative to storage grids at selected positions, i.e., cells in the grids. The invention can be used with manual, semi-automatic, or fully automatic control. The transport mechanism can extend the tray to either of two distances or pallet positions to either side of the tower so that the storage grids of double depth cell construction at the same level on each side of the tower can be served.

The device is capable of handling very heavy loads albeit with a telescopic tray transport which is relatively flat and compact, comprising a combination of telescopic cantilever beams and four hydraulic cylinders coupled to each other in a novel manner and to a drive member. Such drive member is coupled to a series of telescopically arranged drive members, coupled by flexible members, e.g., sprocket chain arrays in such a manner that hydraulic actuation of the first drive member causes an additively increased actuation of the series for telescopically extending the drive members. The combination of actuations effects a telescopic movement of the drive members and of the beams to transport of the pallet laden tray. Such telescopic coaction is simultaneous and reversible so as to move the tray to either side of the tower, and control of the hydraulic cylinder action can effect a half or full distance of tray movement to utilize double depth storage cells for handling two pallets to a cell.

The drive members all nest within each other to form a compact structure, but are not subject to cargo load nor weight stress. Such weight stress is borne by the beams distributed at both sides of the nested drive members and substantially in the same plane to effect compactness. A first pair of beams is secured to the tower frame while a final pair is secured to the tray. Intermediate pairs articulate the first and final pairs thus described, for reversible telescopic load supporting effect on either side of the tower. The load carrying beams slide with respect to each other on intermediate roller bearing arrays.

The tower is driven on a track intermediate the storage gn'ds, there being two rollers supporting the tower each independently driven by an electric motor. Accordingly, very tall towers can be utilized, albeit the higher the tower, the higher the center of gravity. Thus, a lessening of traction of either roller due to forward or rearward pivotal forces on the tower about a roller caused by deceleration or acceleration will not affect drive of the tower since one roller or the other will inherently have traction increased when traction of the other is decreased.

A detailed description of the invention now follows in conjunction with the appended drawing, in which:

FIG. 1 is a front elevation showning the horizontally movable tower and the vertically movable elevator for carrying a tray in relation to the cells of a structural storage grid at one side of the track on which the tower rolls, the tray being extensible towards and away from the plane of the paper;

FIG. 2 is an end elevation of a tower between a pair of storage grids showing the reversible direction of motion of the tray elevator, the tower being movable toward and away from the plane of the paper;

FIG. 3 is a plan view of a storage system having a plurality of towers in movable and parallel array with an infeed conveyor;

FIG. 4A is a front elevation of the upper construction of the tower;

FIG. 4B is a continuation of FIG. 4A showing the construction of the lower portion of the tower;

FIG. 5 is a section generally through 5-5 of FIG. 4B;

FIG. 6A is a vertical section through 6A6A of FIG. 4A;

FIG. 6B is a vertical section through 6B6B of FIG. 4B;

FIG. 6C is a fragmentary perspectiveof an upper corner of the tower;

FIG. 7 is a front elevation showing details of the fingers of a mechanism for horizontally aligning pallets on the tray so as to be centralized thereon;

FIG. 8 is a side elevation of the tray on line 88 of FIG. 7 showing the tray position indicator assembly;

F IG. 9 is a front elevation of the tray showing the relationship of the telescopic drive members, support channels, support rollers and chain and hydraulic drive mechanism;

FIG. 10A is a fragmentary plan view showing the telescopic mechanism for the tray in transported, i.e., extended condition;

FIG. 10B is a fragmentary plan view which is a continuation of FIG. 10A showing the remainder of the telescopic transport mechanism with the tray supported at the end thereof fully extended outwardly for depositing a pallet in a storage cell, or lifting a pallet out of a cell;

FIG. 11A is a section through 1lA-11A of FIG. 10A;

FIG. 11B is a section through 1 1Bl1B of FIG. 10B;

FIG. 12 is a side elevation of the support roller layout on a slide beam of the tray transport mechanism;

FIG. 13 is an end view of one of the support beams of the telescopic transport mechanism;

FIG. 14 is a plan view of the hydraulic system comprising respective pairs of articulated cylinders for actuating the tray in respective directions transversely of the tower wherein the sub FIGS. A, B, and C show progressive extension of a drive member as certain cylinders are pressurized for transportof the tray toward the left;

FIG. 15 is a view similar to FIG. 14, but wherein the sub figures illustrate the progressive drive member positions A, B and C away from the tower wherein the cylinders are pressurized for extension to the right;

FIG. 16 is a diagram of the chain drive of the tray wherein sub FIGS. A, B, and C show central position and full left and right extensions, respectively.

GENERAL DESCRIPTION Referring to FIG. 1, the invention comprises a tower 10 having a pair of spaced structural columns 15 built up of comer angle irons and diagonal cross braces as generally illustrated and supporting for vertical movement a pallet carrier or tray elevator 18 comprising a tray 20 and capable of vertically lifting pallets 24 carrying, e.g., boxed merchandise as illustrated, the vertical arrows indicating the reverse directions of motion of the elevator. The tower is movable reversibly as indicated by the horizontal arrows, being supported on a roller 28 under each column, which rollers travel on a track 32. The lower end of the tower is thus supported and guided on track 32 while the upper end frame 33 of the tower (FIG. 6A) is guided by an angle iron member 36 between guide rollers 38 (FIG. 2) carried by the tower on arm 39.

Referring to FIGS. 2 and 3, the tower rolls between storage grids 40 and 44 made up of structural members in cellular construction in a known manner.

A grid 40 and a grid 44 can be assembled back to back to effect a plurality of bays as illustrated in FIG. 3. Each cell can be double depth horizontally to hold two pallets 24 as illustratedin FIG. 3.

As seen in FIG. 2, tray 20 is extended toward the right for the purpose of moving a pallet 24 containing a load of cartons to be deposited in a cell at 46. Exten sion of the tray is indicated in solid lines, the cargo being stored at the full horizontal depth of the cell, i.e., towards the rear. Another pallet as indicated in phantom at 46' is stored at the front. Obviously, the same extension of the tray can be used for lifting to retrieve a pallet and its cargo. Likewise in FIG. 2, the position of cargoes at 47 and 47'(in phantom) to the left illustrates the reversible movement of the tray 20 as indicated by the dotted arrow.

Thus the tower can move horizontally into alignment in any desired location between a pair of storage grids and the tray elevator can then move vertically. Subsequently the can move transversely horizontally toward or away from the storage grids for depositing or retrieving loads. Obviously, vertical control of the tray elevator is such as to place the tray initially slightly above the spaced cell beams 48 in inserting a pallet and slightly below for withdrawal, final vertical movement of a couple of inches then being had to rest the pallet or lift it. The tray is slightly narrower than the distance between beams 48 as noted in FIG. 5.

The members 48 are support rails on which pallets are stored, and are spaced apart a sufficient distance for tray clearance in moving up or down between them.

FIG. 3 shows a schematic layout whereby the invention can be used for a plurality of storage grids back to back, with a track 32 intermediate such grids 40 and 44 formed in bays and each track being served by a diverter chute 50. Thus, a series of diverter chutes such as 50 are spaced along an infeed conveyor and the diverter device 58 can divert cargo carrying pallets 24 to any chute 50 in accordance with manual or automatic control.

Referring again to FIGS. 1 and 2, the tower carries a control panel60 and a platform 64 on which an operator may stand for manual control of the tower and tray. The tower and tray may likewise be controlled by automatic electronic means from a remote console by conventional equipment, or by computer programming.

Power for motivating the tower is derived from a pair of motors (see FIG. 43) each driving a flanged roller 28 on track 32 via conventional reduction gearing, the motors, rollers and gearing all being supported by the roller shafts 76 with bracing 77 to the columns; FIGS. 4B, 5, and 6B.

The base frame may be made up of welded plates and structural members as illustrated, in any conventional manner.

Referring to FIG. 1, it will be appreciated that the tower can be of any desired height. However, the taller it is the higher the center of gravity. This is especially true if the tray elevator 18 is at some elevated level, and cargo loaded, when the tower is moving in either direction on track 32. Accordingly, assuming that the tower is starting to move from a standstill position, going to the left, the acceleration force will cause a reduction of traction on the left hand roller. However, load remains on the right hand roller for traction effect. Similarly, when the tower slows down, the deceleration causes lessening load on one or the other roller, depending on direction, and braking effect is then applied to the more heavily loaded roller. Therefore, by providing a separate motor 70 for each roller, the traction differential is minimized. Where a tower is set in motion or slowed down with a simultaneously rising load in the tray elevator, the advantage of the independent motor or arrangement is apparent.

The tray elevator motor 80 (FIGS. 48 and 5) is carried by the base frame 75 of the tower and as in the case of the tower drive motors 70 is disposed on a vertical axis, driving the multiple sprocket chains for rotating a shaft on beaming blocks 96 in frame 75 and having a gear 100 at the left end of the shaft as shown in FIG. 4B which will be understood to mesh with the lower loop of the chains 90.

The shaft 95 (FIGS. 4B and 68) has a pair of gears at respective ends keyed thereto around each of which is a tray lifting chain 110. The chains each terminate at their lower ends through a spring tensioned connection (FIG. 68), being thus fastened to the frame of tray elevator structure 18 through the take up bolt 118 and a spring 122. The frame of the tray elevator will be later described. By taking up on a respective bolt via the nut 123 (FIG. 68) chain wear elongation is compensated. Elongation due to load variation is compensated by respective springs 122, adjusted by nut 124. The other ends of the chains 110 (FIGS. 4A, 6A) are ultimately secured at respective points 124 to the tray structure 18 as later described. Chains 110 pass upwardly to the top frame 33 of the tower and around idler gears 128 carried on a shaft 131 having suitable bearing blocks 132 in a box like structure comprised of heavy longitudinal beams 135 which form the rigidifying top frame 33 (FIG. 4A) in conjunction with equally heavy transverse channels 140, for the columns of the tower. The bearing blocks 132 rest on the inner vertical structural iron angle members of the columns 15 (FIGS. 4A, 6A, 6B) specifically on cross brackets 155. I

From the foregoing description it will be understood that energization of motor 80 will raise or lower the tray elevator 18 via chains 110 dependent upondirection of motor rotation (FIGS. 1, 2, 4B, 6A, 6B) drive being had via chains 90 and shaft 95 and associated gears so that both sides of the tray elevator 18 have lifting force applied thereto at the respective connections 124, FIG. 6A.

THE TRAY ELEVATOR Referring to FIGS. 4A, 4B, 5, 6A, 6B, 7 and 8, the

tray elevator 18 comprises a frame having a top beam 200 (FIGS. 4A, 6A) extending between tower columns 15 and secured at its ends on the back of a short channel 202. A pair of transverse beams (FIG. 4A) or channels 205 carry transverse guide rollers 210 that ride (FIG. 4A) on vertical members 145, on tracks 212 welded thereto. The construction is symmetrical at both ends of beam 200. A longitudinal guide roller 218 is carried at each side of the tray elevator in a respective vertical frame channel 220 which form the sides of the elevator frame structure and which are secured at their upper ends to respective pairs of beams 205. Rollers 218 ride on fixed vertical guide bars 222 (FIGS. 5, 6A) intermediate members 145.

The side frame members 220 are secured at their lower ends to the elevator base frame 226 (FIGS. 48, 5, 6B) and the upper flange edges are welded to the flange edges of short channels 202 to form openings for chain passage and the plates 222 welded therein which form the chain end fastenings at 124 (FIG. 6A).

As seen in FIG. 6B the lower ends of chains 1 (one shown) are secured via bolts 118 as heretofore mentioned, passing through ears 227 welded inside channels 220.

The construction is symmetrical as far as the guide roller arrangement at top and bottom (FIGS. 4B, 6B) of the tray elevator is concerned in that guide rollers 230 at the sides of column members 145 are similar to rollers 210. Also, guide rollers 235 are similar to rollers 218, provided to roll on bars 222.

The elevator base frame 226 (FIGS. 4B, 5, 6B, 7, 8) comprises a box beam construction shown in transverse section in FIGS. 6B and 8 and in full line front elevation in FIG. 7, being built up of plates such as 245a, 245b, 245c, 245d, and channel members 245e, 245f in a rigid welded construction suitable for load support. Other types of frame construction can, of course, be used.

The plates 245c and 245d extend longitudinally across the frame 226 construction (FIGS. 7, 9, 10A, 1 1A, 14, at a central area as a main support for the tray transport mechanism later described.

The side channel members 220 are secured at respective sides of the base frame 226. The webs of such channel members 220 form the lateral side walls of frame 226 to some extent by being coplanar with angle iron members 250 (FIG. 5) which carry rollers 230.

The construction permits lift chains 1 10 to be nested within the flanges of the side channel members 220 as seen in FIG. 5. Also nested within such flanges are hydraulic cylinders 255 (FIGS. 5, 6B, 7) pivotally secured to the webs at 258 and having rods articulated via levers 260 to respective shafts 262 having bearing support as by pillow block 265 secured to respective cross plates 245a and 245b of the elevator base from 226. The shafts are on respective sides of tray and each has a pair of spaced fingers 270 (FIGS. 6B, 7) which are thus rockably actuated upon the pressurizing of cylinders 255 to engage the sides of pallets such as 24 in order to center the pallets on the tray 20. The fingers move in unison to the same predetermined inner limits, e.g., as may be provided by identical positioning of identical cylinders 255 and full movement of the piston rods, in the instant case such movement being one of retraction.

TI-IE TELESCOPIC TRAY TRANSPORT Referring to FIGS. 7, 8 and 9, the plates 2450 and 245b support heavy cantilever channel beams 275 on spacers 276 and secured by bolts 278, provided in plurality (FIG. 8), and these beams will be understood to be thus fixed to elevator frame 226. Lateral adjustment bolts 281 provided on side plates 283 secured to the frame 226 effect alignment and parallelism of beams 275.

Referring to FIGS. 9, 10A and 10B, three additional pairs of channel beams 275a, 275b, 275a similar to beams 275 are provided, all coplanar and of progressively smaller size, but all cantilever load carrying beams telescopically connected with each other and ultimately with beams 275, including a final pair of channel beams 275a of smallest size.

Slide bearings 277 (FIGS. 9, 12) are secured to the beams for ease of sliding engagement and precise spacmg.

All such beams except 275 carry groups of rollers 285 (FIG. 12), three rollers to a group, four groups to a beam, which rollers ride the upper and lower surfaces of the channel of the adjoining beam (FIG. 9).

The innermost pair of channel beams 275C carry angle iron beams 290 to which tray 20 is secured (FIGS. 9 and 108). Such support of beams 290 are likewise by groups of rollers 285. It will be apparent from consideration of FIGS. 10A and 10B that the tray 20 is supported for horizontal reversible movement away from and back to or through the tower (as represented by plates 245c and 245d wherein the tray can extend to either side of the tower to the maximum distance provided within predetermined limits, due care being had to provide proper support by two roller groups 285 for all beams within adjoining channels at maximum extension in either direction.

The driving mechanism for tray 20 for reversible motion away from and back to or through the tower comprises three nested drive members or plates 300, 305, 310 (FIGS. 4B, 9, 10A, 10B, 11A, 118). As seen in FIG. 9, the drive members are nested channel shaped plates having progressively wider horizontal flanges and spaced vertical flanges as well as vertically spaced horizontal webs. The horizontal flanges of each drive plate are secured to the lower surfaces of a pair of channel beams. Thus, flange pairs 300a, 305a, 310a are secured to beam pairs 275a, 275b, 275e, respectively, (FIG. 9).

The drive plates may be secured to the beams by bolts (not shown) or in any other suitable manner, and are thus carried by the beams. Bracing tubes 31 1 which have slide bearings 312 are welded to plates 305 and 310.

The drive plates are telescopically movable with respect to each other, the innermost plate 300 being driven hydraulically. Plates 305 and 310 are chain driven from plate 300 as is tray 20via angle iron beams 290, in a manner to be described.

Referring to FIGS. 10A, 11A, and 15, the hydraulic drive for plate 300 comprises four double ended cylinders 350, 355, 360, 365 (FIG. 14). Cylinders 350 and 355 are welded at their rod ends to each other, at 370, as are cylinders 360 and 365 welded at 275. The piston rods 355a and 360a of cylinders 355 and 360 are pivotally connected to each other by a pin 380 having hearing support on a T-slide guide block 385. A T-slide guide bar 390 (also see FIG. 10A) is secured to fixed cross plates 245c and 454 being thus rigidly secured horizontally to the elevator base frame 266. Rod 350a 

1. A stacker crane comprising a tower having a pair of horizontally spaced columns and a traction wheel under each, said columns and wheels being spaced longitudinally in the direction of travel of said stacker crane, a respective traction drive motor for each traction wheel adjacent the respective traction wheel, a tray elevator in the space between said columns and an elevator drive motor for actuating said tray elevator in a vertical path of traverse, said traction drive motors being disposed outside the space between the columns, a pair of spaced lift chains extending vertically and supported by said columns and having upper and lower ends attached to said tray elevator and being spaced substantially the distance between said columns and extending downwardly intermediate said traction wheels below the upper peripheries thereof effecting space between said wheels and said chains to increase the path of vertical traverse of said tray elevator.
 2. A stacker crane as set forth in claim 1, including means at the lower ends of each chain for taking up slack due to chain wear elongation and means to adjust elongation due to load variation.
 3. A stacker crane as set forth in claim 2, both of said means comprising bolt and nut devices and the latter of said means being resilient.
 4. A stacker crane as set forth in claim 1, said towers comprising vertical corner members extending substantially the height of said tower and said tray elevator having guide roller means encompassing said corner members and movable threalong for guidance.
 5. A stacker crane as set forth in claim 1, said tower columns being each comprised of four corner angle irons having diagonal structural bracing therebetween, a top frame extending across said tower and securing said columns, said columns extending into said frame, bearing blocks carried by said columns in said top frame and a shaft extending between said bearing blocks and having sprocket wheels thereon and said lift chains being carried on respective sprocket wheels.
 6. A stacker crane as set forth in claim 1, and comprising a bottom frame for said columns, bearing blocks in said bottom frame disposed below said respective columns and a shaft extending between said bearing blocks and having sprocket wheels thereon and respective lift chains extending around said sprocket wheels, inclduing a drive means between said tray elevator motor and said shaft. 